Is there room for more than one duffin in the U.K.?

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Starbucks' latest baked good is stirring up controversy, with customers accusing the coffee chain of ripping off a bakery that has been selling the product for years.

Starbucks' U.K. shops have just introduced the duffin, a doughnut-muffin hybrid reminiscent of the now-ubiquitous doughnut-croissant blend dubbed the Cronut.

But fans of the London bakery Bea's of Bloomsbury are crying foul. Bea's has been selling duffins since 2011, according to spokesperson Andre Dang.

"They're one of our most popular products and sell out quickly almost every day," Dang told CNBC. "They've been in our customers' consciousness for some time, which is why so many of them tweeted us to let us know that Starbucks were also selling duffins."

Fans of the baked good took to social media in a show of support for Bea's founder, Bea Vo. More than 1,000 tweets with the hashtag #DuffinGate have been posted on Twitter in the past two days, CNBC reported.

"Since launching, we have discovered there are other Duffins out there in the UK including at Bea’s of Bloomsbury, which is great news for muffin and doughnut fans across the country," the statement reads. "However we’d like to make it clear that neither Starbucks nor Rich Products has suggested to Bea’s of Bloomsbury that they will attempt to stop them selling their own Duffins."